1. Technical Field
This disclosure is directed to electronic systems, and more particularly, systems for storing boot code and configuration settings for computer processors.
2. Description of the Related Art
During the start up of a computer system, a processor executes a group of instructions commonly known as boot code. The boot code contains the initial instructions executed by the processor upon being powered up. These instructions may be used to perform various tasks such as performing self-tests, locating and initiating communications with peripheral devices, and locating and loading an operating system. This procedure is commonly referred to as a boot up. Additionally, a processor may access various configuration settings during boot up. Such configuration settings may include operating voltages, operating clock frequencies, information regarding power states, and information regarding portions of the processor that may be enabled or disabled.
Boot code may be implemented on a read-only memory (ROM). Similarly, configuration settings may be accessed by reading a set of programmable fuses also implemented on the processor. The ROM storing the boot code (the ‘boot ROM’) may be implemented on the same integrated circuit die as the remainder of the processor. Changes to the boot code for future instances of the processor may be accomplished by changing masks used during fabrication of the integrated circuit upon which it is to be implemented. The programmable fuses may also be implemented on the same die using fuses that are typically one-time programmable.